1. Field of the Invention
The present invention relates to a small piezoelectric power generator, and more particularly, to a piezoelectric power generator installed at a tire of an automobile to generate power using vibration and variation in air pressure of the tire.
2. Discussion of Related Art
Tire pressure monitoring system (TPMS) for automobiles is system for checking a tire status to support a driver in safely driving his/her car. In recent times, a system in which the TPMS is constituted by a wireless sensor network and a TPMS module is installed at a tire to communicate with the system in real time has been proposed. Therefore, the necessities of research on micro electro mechanical system (MEMS) devices having various functions and the importance of technical development to provide self-sufficient power necessary to drive sensors are being emphasized.
In addition, the TPMS mounted on the tire for an automobile should have the lifespan of 10 years or more. Accordingly, interest in devices that can generate electricity using physical quantities of tire environments, i.e., vibrations or variation in air pressure in the tire, rather than a conventional battery, is increasing.
In operations of sensor or actuator modules in various environments, in order to drive the sensor module with no battery, development of a self-sufficient power generating device still remains as an unsettled question. Researchers are researching wind, solar power, vibrations, and so on, as energy sources. Techniques of supplying energy required to the sensor module applied to the wireless sensor network from the physical quantities and extending an operation time of the sensors may provide more beneficial environments and status determining information to users.
In the conventional art, results of this research include an electricity generating device having a unit device level or a device in which a plurality of the same devices are arranged to supply generated electric power, and a bulk shape of device. In addition, in order to solve a disadvantage of the unit device level of weak power, a technique using an array of devices is being developed. However, a problem with output power of the power supply device still exists.